The present invention is directed to a series of polyester compounds made from the reaction of (a) a difunctional hydroxy compound, specifically polyoxyalkylene glycols, (b) a difunctional carboxylic acid, specifically dimer acid and hydrogenated dimer acid, and (c) a capping carboxylic acid, which only contains one acid group. These compounds are very well suited to the preparation of products for the personal care market.
There has been a long felt need for water-soluble polymers that can be used in personal care applications. The products of choice are polymers, since the high molecular weight afforded by polymers results in less skin penetration. Products that do not penetrate the skin are desirable since they are less irritating to eye and skin, have a more persistent, more pleasant skin feel, and can be used to keep the desired actives on the surface of the skin. Keeping materials applied for topical benefits on the skin make the use of such formulations more effective in topical applications
For many years there have been a number of polymers used in personal care applications based upon the free radical polymerization of monomers that contain reactive vinyl groups. Such products include acrylate esters and amides and vinyl pyrrolidone. These materials have the desired higher molecular weight but also contain unreacted vinyl monomer that is very undesirable in personal care applications.
The ability to make water-soluble or water dispersible polymers that do not contain unreacted monomer would be a key development. One such attempt is the preparation of urethanes. Urethanes however are the reaction product of isocynates, materials, which offer their own, set of problems when applied to the skin.
Polyesters are a class of compounds, which could offer some interest. However, almost all polyesters used in personal care applications contain no water-soluble groups. Typical of this are the oil soluble polymers of U.S. Pat. No. 5,545,692. This patent, issued August 1996 to Koehler et al, describes polyesters of dimer acid, but said esters are of hydrophobic diols. These products are used in plastic lubrication and are water insoluble. They lack the critical polyoxyalkylene groups and are not capped, as are the products of the current invention. The Koehler products are very different in structure, function and application than the polyesters of the present invention.
Objective of the Invention
One objective of the present invention to provide a series of polyester compounds based upon the reaction of (a) a difunctional hydroxy compound, specifically polyoxyalkylene glycols, (b) a difunctional carboxylic acid, specifically dimer acid and hydrogenated dimer acid, and (c) a capping carboxylic acid, which only contains one acid group. These compounds are very well suited to the preparation of products for the personal care market.
It is another object of the present invention to provide a process for conditioning skin with a series of polyester compounds based upon the reaction of (a) a difunctional hydroxy compound, specifically polyoxyalkylene glycols, (b) a difunctional carboxylic acid, specifically dimer acid and hydrogenated dimer acid, and (c) a capping carboxylic acid, which only contains one acid group. Said process encompasses the contacting the skin with an effective conditioning amount of said polyester polymer.
Still other objectives of the present, invention will become apparent as one reads and understands the present disclosure.
The present invention is drawn to a series of polyesters that arc well suited for use in personal care applications. They are the reaction product of (a) a difunctional hydroxy compound, specifically polyoxyalkylene glycols, (b) a difunctional carboxylic acid, specifically dimer acid and hydrogenated dimer acid, and (c) a capping carboxylic acid, which only contains one acid group.
The present invention is also drawn to a process for use of the series of polyesters made by the reaction product of (a) a difunctional hydroxy compound, specifically polyoxyalkylene glycols, (b) a difunctional carboxylic acid, specifically dimer acid and hydrogenated dimer acid, and (c) a capping carboxylic acid, which only contains one acid group.
The proper selection of the components results in the desired application attributes. The difunctional hydroxy compound has to be a polyoxyalkylene compound. This portion of the polyester provides not only crosslinking due to its difunctional nature, but as importantly provides a water-soluble group to the molecule. The difunctional carboxylic acid provides not only the crosslinking ability based upon its difunctional nature, but also provides the oil soluble portion of the molecule. The balance between the oil soluble and water-soluble groups in the polyester molecule account for the surface-active properties of the molecule. Too much water-soluble polyoxyalkylene group and the product lose surfactant properties and becomes merely a water-soluble polymer. Too much oil soluble difunctional carboxylic group and the product lose it surfactant properties and becomes merely a oil soluble polymer. Since the products used in personal care are aqueous, and require some oil loving properties to deposit on the skin, activity at the hair and skin or these products requires a balance between the oil soluble and water-soluble portions of the molecule. Finally, another critical component is the mono-functional carboxylic group, which caps the polymer and provides terminal oil soluble portion to the molecule. This lowers the critical micelle concentration and provides improved skin deposition.